Medical device having electrostatic coating with chemotherapeutic agents

ABSTRACT

A medical device is made of a substrate; and at least one coating electrostatically coated on the substrate or at least one coating electrostatically impregnated with the substrate. The medical device is a device such as a stent, catheter or suture. The medical device is made of a material such as a ceramic, metal alloy or polymer. At least one chemotherapeutic agent and/or at least one active ingredient can be used with the at least one coating.

The present invention relates to the use of electrostatic impregnationto load materials such as binders and flavors onto substrates such asfibers and medical devices made from ceramics, metal alloys, andpolymers. The invention also relates to substrates loaded with materialssuch as binders and flavors, wherein the materials are loaded into or onthe substrates via electrostatic impregnation.

Many substrates are coated with materials such as polymers, polymericbinders, wax binders, flavors, and the like. For example, medicaldevices, such as stents, which are used in the human body, arefrequently made of metal alloys. The stents require coating with apolymer or wax before use in the body. Another example of a substratethat is typically coated, e.g., with a polymer, a wax or the like, isdental floss.

Currently, dental floss has three main consumer needs that are notachieved in all products. These needs are (i) prevention/minimization offraying and shredding during use, (ii) easy insertion and slidingbetween tight teeth and (iii) gentleness to the gums. As used herein,“fraying” means the separation of fibers by the stress placed on thefloss during use between the teeth. As used herein, “shredding” meansthe breaking of fibers by the stress placed on the floss during usebetween the teeth. The minimization of fraying and shredding of dentalfloss is extremely important, as fraying and shredding are the mostfrequently encountered consumer complaints about floss.

Traditionally, floss consists of continuous fibers coated with waxcontaining additives such as flavors, sweeteners and one or more activeingredients. The microcrystalline wax that is currently used holds thefibers together and facilitates the repetitive sliding motion of flossbetween teeth. Shear forces applied to floss during use lead to frayingand shredding of the fibers. Such fraying and shredding occur primarilybecause the stresses applied to the floss during use tend to exceed thecohesive forces of wax that help bond the fibers together.

There are two possible routes that can be adopted in order to overcomethe floss shredding problem. These include making the floss from amonofilament of suitable size or a “psuedo-monofilament”, i.e., bondingthe plurality of filaments in a multifilament structure such that theyare adhered together and function like a monofilament.Pseudo-monofilament dental flosses are very similar to fiber-reinforcedcomposites, in which fibers are impregnated with polymer matrices, whichcan be thermoset or thermoplastic in nature.

Composites are matrixes, e.g., a matrix comprising a polymeric resin,that are reinforced with another material. For fiber composites, thereinforcing material is fibers. The composite may be used as a dentalfloss. A study of the available composite manufacturing techniques leadsto the understanding that two important stages exist. In stage one, thefibers and binder polymers are brought into intimate contact. In stagetwo, heat and pressure are applied in order to impregnate andconsolidate the components. Stage one is crucial, as it brings thematrix polymer and fiber in closer proximity to each other, therebyminimizing the flow length required during consolidation. This firststage is what makes processing techniques used for thermoplasticcomposites different from thermoset composites, due to their higherviscosities.

It is known to overcome this problem by trying to reduce the viscosityof the resin in order to achieve rapid impregnation of the reinforcingfibers. This is called a pre-impregnation processes.

Solvent or solution impregnation has been used primarily where the highviscosity of the matrix material is reduced using solvents orplasticizers by dissolving the polymer in the solvent. The fibers arethen made to pass through a dip bath filled with the solution of matrixmaterial. The fibers are coated and the coated fibers are then passedthrough a series of dryers in order to remove the solvent, therebyproviding the finished composite. The biggest disadvantage of such aprocess is environmental concerns regarding use of the solvent. Inaddition, manufacturing speed is very low, and thus manufacturing costsare increased.

The process described above requires dissolving a coating material in asolvent prior to coating a substrate. Dissolving the coating materialmay be undesirable, as there is an environmental concern over volatileorganic compounds. Therefore, there is a need for a process of coating asubstrate that does not require dissolving a coating in a solvent.

Powder impregnation is a more versatile process, as it will process bothlow and high viscosity resins as long as they can be obtained in thepowder form, and the process is relatively simple.

Investigators at Georgia Tech have developed a system wherein glassfibers are spread using up to 8 Teflon* coated rollers after which thespread fibers have a powder deposited thereon using a deposition systemdeveloped by Electrostatic Technology Incorporated (ETI). In thissystem, powder particles are charged and are then electrostaticallydeposited onto the glass fiber. The above-mentioned rollers were found,however, to cause damage to the fiber and a transition was then made toa different fiber spreading technology known as pneumatic venturispreading. This effort lead to the issuance of U.S. Pat. No. 5,094,883.In the patent, the importance of flexible fiber impregnation productionwas taught for applications such as braiding and weaving.

None of the dental floss patents of which the inventor is aware haveapplied a powder technology approach for coating the substrate fibers ofthe dental floss with polymers. There is a continuing need for a processof coating substrates such as fibers and medical devices which does notrequire dissolving a coating in a solvent.

The present invention provides a process including: providing asubstrate; and electrostatically coating the substrate with at least onecoating material. In another embodiment, the present invention providesa substrate coated by electrostatic impregnation. The invention utilizeselectrostatic powder coating technology to coat a substrate withmaterials such as waxes; thermoplastic polymers; additives such asspray-dried flavors and sweeteners; active ingredients such as sodiumfluoride; abrasives; etc. This method can be used for coating anysubstrate including, but not limited to films, non-wovens, monofilamentfibers, multi-filament fibers, medical devices, hair, sutures, and metaldevices as long as the coating materials are in a powder form. Thepreferred substrates are monofilament fibers, multi-filament fibers, andmedical devices. The coated fibers may be useful in applications suchas, but not limited to, dental tapes and dental floss. The medicaldevices may be made of ceramics, metal alloys, or polymers. The medicaldevices may be useful in applications such as, but not limited to,stents and polymer tubes such as catheters.

The approach for electrostatically coating floss adopted in the presentinvention is to prepare a pseudo-monofilament by using waxes orthermoplastic polymers to adhere the fibers to each other before coatingthe resulting pseudo-monofilament with a desired coating compositionwhich may include, for example, waxes, thermoplastic polymers, flavorsand other additives. Some of the advantages of using waxes orthermoplastic polymers as the coating materials are the ease ofprocessability, toughness, durability, long shelf life, lack ofcross-linking chemical reactions and relatively high manufacturingspeed. The drawbacks, however, are very high melt viscosities (in therange of 10⁴ poise) which lead to challenges in the areas of total fiberwet-out, interface control and mass production.

In the present invention, wax or polymer powder impregnation has beenchosen to accomplish the challenge of bringing the fiber and matrix intocontact by using an electrostatic deposition chamber. The technique hasthe ability to support continuous production of fibrous substrates whichcan then be integrated into a consolidation line that can use techniquessuch as calendering, hot-gun heating, filament winding and hand lay-upto apply pressure and heat in order to produce the floss product. Oncethe fibers have been bonded together, wax and other additives can beapplied to the bonded substrate.

The physics of charging polymeric particles is not always easy tocomprehend and is far from being completely tied to the chemistry of thepolymer powder. However, a considerable amount of research has been donein the area with regard to electrostatic spray guns in the painting andcoating industry.

Powders acquire charge in two ways: tribocharging and corona charging.Corona charging results when particles receive a charge fromelectrically charged air. Tribocharging occurs when powder, duringtransportation from a reservoir to the spray gun or coater bed,undergoes frictional contact with an unsymmetrical surface. Thisunsymmetry could be due to velocity, temperature or chemicalcomposition. The polarity and magnitude of the tribocharge depend on thenature of the powder, the travel velocity, and the nature of the contacttubing. Formulation chemistry of the polymer could also determine thenature, i.e., positive or negative, of the acquired charge. Usually thecharging is higher at lower transportation rates and decreases astransportation rates increase. On the other hand, corona charging occursin the region between the corona glow and the substrate. For particlesbeyond a certain size (>0.5 microns) field charging predominates. Belowa size of 0.2 microns however, the charge diffuses through the air.

According to theory, the saturation charge per ball-shaped particle isdirectly proportional to the square of the particle radius and inverselyproportional to its mass. The shape of the particle was found to notdeviate in most cases from the ball-shape and so approximations madewith regards to the spherical nature of the particle in theoreticalcalculations are still fairly accurate. In regard to the sign (i.e.,positive or negative) and magnitude of the charge the electron affinityof the elements or functional groups bound to the carbon atoms and theirstereometric arrangement in the macromolecule proves to be decisive.

A comparison shows that the increasing tendency to charge negativelymoves in accordance with the increasing work function of the electron[poly methyl(methacrylate), polyethylene, poly(vinylchloride),poly(tetrafluoroethylene)], while materials with the lowest workfunctions tend to charge positively (e.g., polyamide). In spray gunapplications, aerodynamic forces are responsible for transporting thepowder towards the object and electrostatic forces are responsible oncethe powder is near the substrate in order to facilitate good wrapping ofthe coating around the fibers.

Suitable fibers to be used in the present invention include, but are notlimited to, natural fibers such as cellulose, cellulosic fibers, andrayon; polyolefins such as polyethylene and polypropylene; polyesterssuch as polycaprolactone (“PCL”), poly(ethylene terephthalate) (“PET”),poly(butylene terephthalate) (“PBT”), and Vectran (Trademark ofHoechst-Celanese); polyamides such as nylon 6, nylon 11, nylon 12, andnylon 6,6; poly(ether-amides) such as, but not limited to, Pebax® 4033SA and Pebax® 7233 SA (Trademark of Elf Atochem); poly(ether-esters)such as, but not limited to, Hytrel® 4056 (Trademark of DuPont) andRiteflex® (Trademark of Hoechst-Celanese); fluorinated polymers such aspoly(vinylidine fluoride) and poly(tetrafluoroethylene); andcombinations thereof, including bicomponent fibers, which may becore-sheath fibers. Texturized fibers may also be used.

The bicomponent fibers may have cross-sectional shapes such as round;trilobal; cross; and others known in the art. The core-sheathbicomponent fibers are typically made such that the sheath of the fibersutilizes a lower melting point polymer than the core polymer. Suitablepolymers for the core include polyamides such as, but not limited to,nylon 6, nylon 11, nylon 12, and nylon 6,6; polyesters such as, but notlimited to, PET and PBT; poly(ether-amides) such as, but not limited to,Pebax® 4033 SA and Pebax® 7233 SA (Trademark of Elf Atochem);poly(ether-esters) such as, but not limited to, Hytrel® 4056 (Trademarkof DuPont) and Riteflex® (Trademark of Hoechst-Celanese); polyolefinssuch as, but not limited to, polypropylene and polyethylene; andfluorinated polymers, such as, but not limited to, poly(vinylidenefluoride); and mixtures thereof. Nylon 6 and polypropylene arepreferred.

Suitable polymers for the sheath include polyolefins such as, but notlimited to, polyethylene (“PE”) and polypropylene; polyesters such as,but not limited to, PCL; poly(ether-amides) such as, but not limited to,Pebax® 4033 SA and Pebax® 7233 SA (Trademark of Elf Atochem);poly(ether-esters) such as, but not limited to, Hytrel® 4056 (Trademarkof DuPont) and Riteflex® (Trademark of Hoechst-Celanese); elastomersmade from polyolefins, for example Engaged elastomers (Trademark ofDuPont-Dow); poly(ether urethanes) such as, but not limited to, Estane®(Trademark of BF Goodrich); poly(ester urethanes) such as, but notlimited to, Estane® (Trademark of BF Goodrich); Kraton® polymers(Trademark of Shell Chemical Company) such as, but not limited topoly(styrene-ethylene/butylene-styrene); and poly(vinylidene fluoride)copolymers, such as, but not limited to, KynarFlex® 2800, (Trademark ofElf Atochem). Pebax® polymers, polyethylene, and PCL are preferred.

The ratio of the two components of the core-sheath fibers can be varied.All ratios used herein are based on volume percents. The ratio may rangefrom about 10 percent core and about 90 percent sheath to about 90percent core and about 10 percent sheath, preferably from about 20percent core and about 80 percent sheath to about 80 percent core andabout 20 percent sheath, more preferably from about 30 percent core andabout 70 percent sheath to about 70 percent core and about 30 percentsheath. The sheaths of the bicomponent fibers may be fused prior toelectrostatic coating.

The substrates are electrostatically coated with at least one coatingcomposition. Suitable first coatings to be used in the present inventioninclude, but are not limited to, poly(ethylene oxide); poly(ethyleneglycol); hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene;waxes such as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.

Suitable second coatings to be used in the present invention include,but are not limited to, poly(ethylene oxide), poly(ethylene glycol),hydroxyethyl cellulose, hydroxypropyl cellulose, polyethylene, waxessuch as microcrystalline wax, and polycaprolactone. The coatings maycontain flavors, such as, but not limited to, natural and syntheticflavor oils, such as mint and cinnamon. The flavor oils may be used asis, or may be encapsulated in or supported on a carrier such as starchor modified starch.

The process of the invention may also be useful for orienting shortbicomponent fibers perpendicular to the axis of a substrate, then fusingthe short bicomponent fibers to the substrate. The length of the shortbicomponent fibers may range from 1 mm to 5 mm. After the shortbicomponent fibers are oriented onto the substrate by electrostaticimpregnation, they are fused to the substrate by heat at a temperatureappropriate to melt the outer surface of the bicomponent fiber.

Additional materials that may be included in the coatings include, butare not limited to, sweeteners such as bulk sweeteners, includingsorbitol and mannitol, and intense sweeteners including aspartame andsodium saccharin, as taught by European Patent Application EP 919,208,hereby incorporated by reference for the disclosure relating to waxesand sweeteners; abrasives, such as silica; dentrifices; chemotherapeuticagents; cleaners; and whiteners. Examples of suitable additives aredisclosed in U.S. Pat. No. 5,908,039, the disclosure of which is herebyincorporated by reference. Any of the foregoing materials may be used inencapsulated form.

The amount of wax, flavor, and other additives typically coated onfibers to make floss is known in the art. Typically, the coatingcomposition is added at from 2 weight percent to 60 weight percent,based on the weight of the fibers.

Suitable medical devices to be used in the present invention include,but are not limited to, medical devices made from ceramics, metalalloys, and polymers, such as stents, and polymer tubes such ascatheters. The medical devices may be coated with the same waxes and inthe same manner as mentioned above.

Many factors were important in determining how to prepare examples ofthe present invention. The selection of materials was based on a numberof chemical and physical parameters of the polymer and the fiber. Amongthese, the melting point (T_(m)) and degradation temperature (T_(d)) areimportant as they determine issues regarding material selection andprocessing conditions. The chemical structure of the polymers willinfluence the adhesion of the deposited material to the substratefibers.

Processing conditions further involve operating furnace temperature,residence time in the furnace (which influences line speed) and powderconcentrations. Physical parameters such as powder particle size (meanand distribution), density, melt viscosity, electrical conductivity,etc. are among the important ones that determine the depositioncharacteristics. Crystallization kinetics of the binder polymer alsomust be considered as it has an influence on the morphology/structure ofthe polymer once it is cooled down from the melt during theconsolidation stage. Coating polymers and fibers were chosen for theexamples considering all the factors, and are summarized with theirproperties in Tables 1A and 1B. TABLE 1A Particle T_(M) T_(D) PolymerProducer Size (° C.) (° C.) Polycaprolactone Union 60 60 343 (Tone 767)Carbide Polyethylene Union 100 65 250 Oxide Carbide (WSR-N-10-100- Reg)Polyethylene Union 100 65 250 Oxide Carbide (WSR-N-80-100- NF) Nylon 11Elf NT 185 436 (Besno) Atochem Poly (vinylidene Elf 200 165 374Fluoride) Atochem (Kynar 711) PVDF Copolymer Elf 200 145 363 (Kynar-FlexAtochem 2801) Poly (ether- Elf NT 160 232 amide) Atochem (Pebax 4033-SA)High Density Hoechst- 120 130 NT Polyethylene Celanese (HDPE GHR 8110)Hydroxypropyl Hercules 100 190 350 cellulose (Klucel [EXS Pharm.])(particle size is in mesh)NT = not tested

TABLE 1B Tenacity T_(M) T_(D) Fiber Type Construction Denier (g/d) (°C.) (° C.) Nylon 6,6 Untwisted 630 8 255 442 Air- Entangled 3 dpf Nylon6 Untwisted 1400 5 220 446 Air- Entangled 3 dpf Polypropylene Untwisted630 8 162 301 Air- Entangled 3 dpf Teflon Monofilament 1200 5 N/A NTPolyester Untwisted 400 23 331 NT (Vectran) 5 dpfdpf = denier/filament

The powder coating process is shown schematically in FIG. 1. The coatingline consists of a feed spool, grounding unit, electrostatic coater,furnace/oven and take-up winder. The feed spool is mounted on a metallicpost that facilitates easy unwind of the fiber during operation. Thefiber is then made to pass through an eyelet that is connected to aground source to allow for grounding of the fiber. The fiber then passesthrough a tensioning device made of ceramic rods that can be adjusteddepending on the desired packing conditions of the powder in the fibermatrix. The fiber then passes through openings provided at each end ofthe coater.

A B-60 coater (available from Electrostatic Technology Incorporated, asubsidiary of Nordson Corporation, Branford, Conn.) was used to conductthe processes set forth in the examples. The coater comprises a powderfeeder connected to it that feeds powder, which is held in a hopper,into the rear end of the bed. A photohelic gauge placed in the bedmeasures the level of powder in the bed and ensures that a constantlevel of powder is maintained during the coating operation. Arefrigerator unit ensures the delivery of clean, moisture and oil freeair into the plenum of the coater, and a powder collector provides forcollection of powder that is vacuumed out of the bed during operation.The coater also comprises a fire detection device and a vortex tube toassist in the formation of the powder cloud.

The powder coated fiber exits the deposition chamber and then passesthrough a furnace. A suitable furnace and is made by Lindberg andGlenro. The furnace has a spilt lid that is made to open and close viaair actuated arms. The fiber then moves through an eyelet onto a corespool using a Leesona rewinder. The line speed can be controlled by theLeesona rewinder and is measured using a digital tachometer.

A layer of polymer powder was fluidized in the bed, which wasconstructed of a plastic material. The powder was fluidized by air thatwas charged negatively in the plenum of the coater. The air was keptclean and free of moisture and oil by passing it through a refrigerationunit. The air was then made to pass through the air plenum andencountered a mesh of electrodes that were charged by a highly negativedirect current supply.

Negative coronas used as negatively charged powder particles tend todeposit more uniformly and efficiently than positively charged onesbecause of their relative resistance to electric breakdown. Theelectrons generated in the glow region of the negative corona quicklyattach themselves to electronegative gas molecules such as oxygen in theair to form negative ions. The negatively charged air then passedthrough a porous ceramic or plastic bed to contact the powder. Fieldcharging or ion bombardment then transferred some of the ions to thepowder particles thereby generating an aerated, negatively charged cloudof powder in the bed. This indirect charging of the powder by the airalong with the separation of the charging mesh from the powder makes thefluidized bed process different from other powder techniques such aspowder spray gun and triboelectric charge guns. The substrate, which inthe present case was the fiber, was then grounded in order to generate asufficient potential difference to facilitate electrostatic deposition.

The amount of polymer binder added to the fibers was the main dependentvariable for the design of experiments. The powder coating variablesthat could have an impact on the add-on are bed fluidization flow rate(“m³/sec”), electrostatic voltage (kilovolts, “kV”) and line speed(meters per minute). The other variables that can be controlled on thecoater are bed air pressure, vortex flow rate and vortex air pressure.It was determined that none of these latter variables influenced theadd-on significantly.

The vortex tube settings were changed to create the powder cloud andonce the cloud was generated, the settings were kept constant throughoutthe experiment. The bed agitator was turned on whenever needed, but wasavoided as much as possible, as it was seen to reduce the add-on due toadditional turbulence in the powder cloud. In general, whereverpossible, a two parameter, three level design of experiments wasconducted. The variables were varied within the following limits:

-   -   Bed fluidization flow rate (m³/sec): Low (0.006); Medium        (0.010); and High (0.014)    -   Electrostatic voltage (kV): Low (0 or no voltage); Medium        (20.2); and High (40.4)

It was important to determine the furnace temperature in order tooptimize the polymer fusion and bonding on the fiber. A visualexperiment was carried out on nylon 6 fibers and polyethylene oxidebinder. The residence time in the furnace for a line speed of 10 m/minwas calculated based on the length of the furnace (approximately 1meter) to be 6.3 seconds.

Fiber was coated at a bed flow rate of 0.014 m³/sec and electrostaticvoltage of 40.2 kV and was then inserted into the furnace at a selectedtemperature and held there for 6.3 seconds. Optical microscopy wasperformed to check the melt morphology of the polymer on the fibers. Thefurnace temperature was then raised and a freshly coated sample wasexposed to the temperature. This was done until a temperature wasreached at which melt occurred. It was observed that a good coating wasformed on the fibers at a furnace temperature of 265° C.

The procedure described above was utilized to determine the furnacetemperature for a given set of materials and process conditions. Theresidence time in the oven can be increased by using longer ovens or bywrapping the coated yarn in grooves of metallic rollers mounted onpulleys in the heated section of shorter ovens.

EXAMPLE 1 Polyamide Multi-Filaments/Water Soluble Polymer CoatingSystems

(a) Nylon 6 Multi-Filaments/Poly(Ethylene Oxide)

Poly(ethylene oxide) [PEO] N-80 grade was used to coat a nylon 6multi-filament structure comprising 467 filaments, each filament havinga denier of 3. Tables 2 and 3 show the add-on (%) of PEO as a functionof electrostatic voltage and bed flow rate, respectively, at an oventemperature of 260° C. and a line speed of 16 m/min. The add-onincreases with increasing voltage but decreases beyond a voltage valueof 40 kV. On the other hand, the trend with respect to bed flow rateindicates a strong monotonic dependence where the add-on increases withincreasing flow rate. PEO powder was uniformly dispersed and fused onthe nylon 6 fibers as was observed by scanning electron microscopy.TABLE 2 Bed Flow Rate Electrostatic Voltage Add On (m³/sec) (KV) (%)0.006 0 1.73 0.006 20 9.8 0.006 40.4 10.2 0.006 60.2 1 0.010 0 4.170.010 20 22.64 0.010 40.4 24.14 0.010 60.2 3.75 0.014 0 7.14 0.014 2028.57 0.014 40.4 36.21 0.014 60.2 5 0.014 80.4 5.35

TABLE 3 Electrostatic Voltage Bed Flow Rate Add On (KV) m³/sec (%) 00.006 1.73 0 0.010 4.17 0 0.014 7.14 20.6 0.006 9.8 20.6 0.010 22.6420.6 0.014 28.57 40.3 0.006 10.32 40.3 0.010 24.14 40.3 0.014 36.21 60.20.006 1 60.2 0.010 3.75 60.2 0.014 5 80.4 0.014 5.35(b) Nylon 6,6 Multi-Filaments/Poly(ethylene Oxide):

PEO N-80 was used to coat a nylon 6,6 multi-filament structurecomprising 210 filaments, each having a denier of 3, at a furnacetemperature of 237° C. Tables 4 and 5 show the add-on of PEO as afunction of voltage and flow rate at line speeds of 11 m/min and 17m/min, respectively. As seen from the Tables, regardless of the linespeed, the add-on is very sensitive to bed flow rate, with increasingflow rates resulting in higher add-on. The trend with voltage is thesame as in the previous case with the existence of a saturation voltagebeyond which increasing voltage results in a drop in add-on. Thesaturation voltage in the present case appeared to be 40 kV. The add-onalso seemed to be higher at 17 m/min as compared to 11 m/min, but higherspeeds did not support this trend. Scanning electron micrographs showedthat PEO was uniformly coated on the nylon 6,6 fibers. TABLE 4 Add-On(%) Voltage 0.006 m³/sec 0.014 m³/sec 0 5.13 19.23 20 7.14 22.22 40 3.3315.69 60 3 15.38

TABLE 5 Add-On (%) Voltage 0.006 m³/sec 0.014 m³/sec 0 2.5 17.07 20 3.6424.1 40 3 26.67 60 1 22.73 80 0.6 23

A study was conducted after coating nylon 6,6 with 20% PEO at an oventemperature of 235° C., voltage of 30 kV, flow rate of 0.013 m³/sec, bedpressure of 45 psi, vortex pressure of 20 psi and line speed of 11m/min. Table 6 summarizes the results of a consumer test of PEO coatednylon 6,6 floss. The data (percent of people who indicate the flosspasses each test) shows that the PEO coated floss performed well,particularly at ease of sliding between teeth and being gentle on thegums. TABLE 6 Property Percent Pass Sliding easily between teeth 63Being gentle to the gums 55 Cleaning effectively between all teeth 24(c) Nylon 6,6 Multi-Filaments/Hydroxypropyl Cellulose:

Nylon 6,6 was coated with hydroxypropyl cellulose.

Tables 7 (line speed of 11 m/min, oven=235° C.) and 8 (line speed of 16m/min, oven=255° C.) show that the add-on of hydroxypropyl cellulose(“HPC”) was dependent on the bed flow rate which was the dominantfactor. HPC powder possessed large amounts of charge as received fromthe supplier. The powder floated and tended to melt onto the fiber oncedeposited. TABLE 7 Voltage Add-on (%) at Add-on (%) at (kV) 0.006 m³/sec0.014 m³/sec 0 0 9.09 40 2 11.76 80 1.2 12.5

TABLE 8 Voltage Add-on (%) at Add-on (%) at (kV) 0.006 m³/sec 0.014m³/sec 0 0 14.81 40 3.57 18.18 80 4 15

EXAMPLE 2 Polyester Multi-Filaments/Water Insoluble Polymer CoatingSystems

(a) Vectran Multi-Filaments/High Density Polyethylene:

Vectran is a high performance/high temperature fiber made from liquidcrystalline polyester and is commercially available fromHoechst-Celanese. A furnace temperature of 310° C. was used to melt thewater-insoluble polyethylene coating material onto the Vectran® fiber ata line speed of 17 m/min. Table 9 shows that in order to achieve higheradd-ons of polyethylene, high flow and voltage was essential. TABLE 9Voltage Add On (KV) (%) 0 9.35 20.2 8.38 40.3 8.1 60.1 14.8 80.5 55

The flow rate required to achieve the above add-ons was 0.014 m³/sec.

EXAMPLE 3 Fluoropolymer Monofilament/Water Soluble Polymer CoatingSystems

(a) Poly(tetrafluoroethylene) (“PTFE”) Monofilament/Poly(ethyleneoxide):

PTFE monofilament was coated with a non-wax water-soluble polymer, i.e.,poly(ethylene oxide), to increase the coefficient of friction. The PTFEmonofilament was generally rectangular in transverse cross-section, witha width of about 2-3 mm and a thickness of about 0.08-0.13 mm. Thetemperature was 320° C. at a line speed of 27 m/min. Table 10 shows theadd-on of PEO on the PTFE monofilament tape, and it was observed thatbeyond 20 kV voltage the add-on drops as was seen earlier. This showsthat the trend of add-on versus voltage is independent of substrategeometry, i.e., cylindrical versus flat fibers. PTFE was alsosuccessfully coated with a mixture of multiple powders such as PEO,spray-dried peppermint flavor and sodium saccharin. TABLE 10 VoltageAdd-On (%) (kV) 0.006 m³/sec 0.010 m³/sec 0.014 m³/sec 0 10.26 10.22 NT21.0 18.39 18.7 21.62 40.2 10.58 11.9 NT 60.2 7.5 9.1 NT 80.4 9.1 11.2NT

Tables 11A and 11B summarize all the coating experiments that wereconducted on different classes of fibers using different polymer coatingsystems and the preferred conditions for each set of materials. The mainvariables were bed pressure (0.006 to 0.014 m³/sec), voltage (0 to80-kV) and line speed (6 to 64 m/min for Nylon 6/PEO N80, and 11 to 17m/min for the rest of the materials tested). The furnace temperature waschanged based on the fiber/polymer combination. If desired, furtherconsolidation can be carried out on the powder-coated fibers in order toprepare a thoroughly impregnated product. A combination of heat andpressure can be used to drive the polymer inside the fibers that willproduce a void free product. Using the viscous flow of the polymerthrough the fibrous network and the elastic deformation of the fibernetwork, a consolidation model can be developed. TABLE 11A PreferredConditions Fiber Polymer Pressure Voltage Speed Comments Nylon 6 PEO N800.014 40.4 kV 11 m/min Oven = 260° C. Binder = 1.75% to 31% Nylon PEON80 0.014 20.2 kV 11 m/min Oven = 237° C. 6,6 Binder = 1.5% to 27%Reduced add on due to turbulence PEG 8000 Larger particle size, Highdensity/ poor floatation, Low molecular weight, good melt Klucel 0.01440.2 kV 17 m/min Powder was very fine, Extremely cohesive, Agitator hadto be used, Feed hopper could not be used

TABLE 11B Preferred Conditions Fiber Polymer Pressure Voltage SpeedComments Nylon Kynar 711 Kynar powders - 6,6 Kynar high Flex densities,PCL fine particle size, PCL did not charge due to its size, grindingdown was not possible Polypro- PEO N80 0.010 20.2 kV 11 m/min Fiberpylene performed very well, low melting point made coating difficultVectran HDPE 0.014 80.2 kV 17 m/min Powder was extremely heavy, oven =310° C. Teflon HDPE 0.014 80.2 kV 17 m/min Powder was extremely heavy,oven = 310° C., good melt but poor adhesion PEO N80, 0.006 20.2 kV 27m/min Excellent flavor, floatation, saccharin oven = 320° C., increasedblend ratio

EXAMPLE 4 Selection Process for Polymer Powders Based on Powder Aeration

It is necessary to understand powder aeration to predict the coatingperformance of polymer powders. In order to understand thisquantitatively, experiments were carried out on several powders toobtain their bulk and tapped densities. In this experiment, a cleangraduated cylinder was taken and weighed (W₁). 50 cc. of powder was thenpoured into the cylinder and weighed again (W₂). Weights were recordedto 5 decimal precision. The aerated/bulk density was then computed usingequation (1). $\begin{matrix}{{\rho_{b} = \frac{W_{2} - W_{1}}{50}},} & (1)\end{matrix}$whereρ_(b) is the bulk density in grams/cc.

In order to obtain the tapped density the same measurements were madewith a minor difference. After the powder was poured into the cylinder,it was tapped 50 times in order to compact it and powder was added tomaintain a 50 ml volume. The cylinder was then weighed (W₃). Equation 1was used after substituting W₃ for W₂, and the tapped density wasobtained in grams/cc. Table 12 lists the bulk and tapped densities ofthe different polymers. The fused density in the table represents thedensity of a block of material. TABLE 12 Bulk Density Tapped DensityFused Density Polymer (g/cc) (g/cc) (g/cc) Polyethylene Oxide 0.46-0.500.54 1.2 WSR-N-10-100-Reg WSR-N-80-100-NF Polycaprolactone 767 0.52 0.611.15 Polyethylene Glycol 0.54 0.82 1.03 Polyethylene GHR 8110 0.47 0.510.95 HPC (Klucel) 0.32 0.39 1.16

The differential densities (fused density−tapped density) of the polymerparticles were plotted (log-log) as a function of mean particle size (inmicrons). It appears that the relationship of these polymer propertiesis critical to the polymer's fluidization properties, such asaeratability, cohesiveness, sand-like properties, and spoutability. Thedata can be used as a guide in selecting powders for fluidized-bedcoating applications. For example, PEO and HPC are more aeratable thanPolyethylene glycol and Polyethylene GHR 8110 (a high densitypolyethylene). Therefore, PEO and HPC are more easily fluidized.

1-14. (Cancelled)
 15. A medical device comprising: a substrate; and atleast one coating electrostatically coated on the substrate.
 16. Themedical device according to claim 15, wherein the substrate is made of amaterial from the group consisting of ceramics, metal alloys orpolymers.
 17. The medical device according claim 16, wherein the medicaldevice is from the group consisting of stents, catheters or sutures. 18.The medical device according to claim 17, further comprising at leastone chemotherapeutic agent with the at least one coating.
 19. Themedical device according to claim 17, further comprising at least oneactive ingredient with the at least one coating.
 20. The medical deviceaccording to claim 15 further comprising at least one chemotherapeuticagent with the at least one coating.
 21. The medical device according toclaim 15, further comprising at least one active ingredient with the atleast one coating.
 22. The medical device according to claim 15, whereinthe at least one coating comprises a first coating and a second coating.23. The medical device according to claim 22, wherein the first coatingis from the group consisting of poly(ethylene oxide); poly(ethyleneglycol); hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene;waxes such as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 24. The medical device according to claim 23, whereinthe second coating is from the group consisting of poly(ethylene oxide);poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropyl cellulose;polyethylene; waxes such as microcrystalline wax; polyvinylidenefluoride and polycaprolactone.
 25. The medical device according to claim17, wherein the at least one coating comprises a first coating and asecond coating.
 26. The medical device according to claim 25, whereinthe first coating is from the group consisting of poly(ethylene oxide);poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropyl cellulose;polyethylene; waxes such as microcrystalline wax; polyvinylidenefluoride and polycaprolactone.
 27. The medical device according to claim26, wherein the second coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 28. The medicaldevice according to claim 18, wherein the at least one coating comprisesa first coating and a second coating.
 29. The medical device accordingto claim 28, wherein the first coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 30. The medicaldevice according to claim 29, wherein the second coating is from thegroup consisting of poly(ethylene oxide); poly(ethylene glycol);hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene; waxessuch as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 31. The medical device according to claim 19, whereinthe at least one coating comprises a first coating and a second coating.32. The medical device according to claim 31, wherein the first coatingis from the group consisting of poly(ethylene oxide); poly(ethyleneglycol); hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene;waxes such as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 33. The medical device according to claim 32, whereinthe second coating is from the group consisting of poly(ethylene oxide);poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropyl cellulose;polyethylene; waxes such as microcrystalline wax; polyvinylidenefluoride and polycaprolactone.
 34. A medical device comprising: asubstrate; and at least one coating electrostatically impregnated withthe substrate.
 35. The medical device according to claim 34, wherein thesubstrate is made of a material from the group consisting of ceramics,metal alloys or polymers.
 36. The medical device according claim 35,wherein the medical device is from the group consisting of stents,catheters or sutures.
 37. The medical device according to claim 36,further comprising at least one chemotherapeutic agent with the at leastone coating
 38. The medical device according to claim 37, furthercomprising at least one active ingredient with the at least one coating.39. The medical device according to claim 34, further comprising atleast one chemotherapeutic agent with the at least one coating.
 40. Themedical device according to claim 34, further comprising at least oneactive ingredient with the at least on coating.
 41. The medical deviceaccording to claim 34, wherein the at least one coating comprises afirst coating and a second coating.
 42. The medical device according toclaim 41, wherein the first coating is from group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 43. The medicaldevice according to claim 42, wherein the second coating is from thegroup consisting of poly(ethylene oxide); poly(ethylene glycol);hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene; waxessuch as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 44. The medical device according to claim 36 whereinthe at least one coating comprises a first coating and a second coating.45. The medical device according to claim 44, wherein the first coatingis from the group of poly(ethylene oxide); poly(ethylene glycol);hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene; waxessuch as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 46. The medical device according to claim 45, whereinthe second coating from the group consisting of poly(ethylene oxide);poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropyl cellulose;polyethylene; waxes such as microcrystalline wax; polyvinylidenefluoride and polycaprolactone.
 47. The medical device according to claim37, wherein the at least one coating comprises a first coating and asecond coating.
 48. The medical device according to claim 47, whereinthe first coating is from the group consisting of poly(ethylene oxide);poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropyl cellulose;polyethylene; waxes such as microcrystalline wax; polyvinylidenefluoride and polycaprolactone.
 49. The medical device according to claim48, wherein the second coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 50. The medicaldevice according to claim 38, wherein the at least on coating comprisesa first coating and a second coating.
 51. The medical device accordingto claim 50, herein the first coating is from the group poly(ethyleneoxide); poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropylcellulose; polyethylene; waxes such as microcrystalline wax;polyvinylidene fluoride and polycaprolactone.
 52. The medical deviceaccording to claim 51, wherein the second coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 53.A stent comprising: a substrate; and at least one coatingelectrostatically coated on the substrate.
 54. The stent according toclaim 53, wherein the substrate is made from a ceramic material.
 55. Thestent according to claim 53, wherein the substrate is made from a metalalloy.
 56. The stent according to claim 53, wherein the substrate ismade from a polymer.
 57. The stent according to claim 53, furthercomprising at least one chemotherapeutic agent with the at least onecoating.
 58. The stent according to claim 54, further comprising atleast one chemotherapeutic agent with the at least one coating.
 59. Thestent according to claim 55, further comprising at least onechemotherapeutic agent with the at least one coating.
 60. The stentaccording to claim 56, further comprising at least one chemotherapeuticagent with the at least one coating.
 61. The stent according to claim53, further comprising at least one active ingredient with the at leastone coating.
 62. The stent according to claim 54, further comprising atleast one active ingredient with the at least one coating.
 63. The stentaccording to claim 55, further comprising at least one active ingredientwith the at least one coating.
 64. The stent according to claim 56,further comprising at least one active ingredient with the at least onecoating.
 65. The stent according to claim 53, wherein the at least onecoating comprises a first coating and a second coating.
 66. The stentaccording to claim 65, wherein the first coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 67.The stent according to claim 66, wherein the second coating is from thegroup consisting of poly(ethylene oxide); poly(ethylene glycol);hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene; waxessuch as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 68. The stent according to claim 65, furthercomprising at least one chemotherapeutic agent with the at least onecoating.
 69. The stent according to claim 65, further comprising atleast one active ingredient with the at least one coating.
 70. A stentcomprising: a substrate; and at least one coating electrostaticallyimpregnated with the substrate.
 71. The stent according to claim 70,wherein the substrate is made from a ceramic material.
 72. The stentaccording to claim 70, wherein the substrate is made from a metal alloy.73. The stent according to claim 70, wherein the substrate is made froma polymer.
 74. The stent according to claim 70, further comprising atleast one chemotherapeutic agent with the at least one coating.
 75. Thestent according to claim 71, further comprising at least onechemotherapeutic agent with the at least one coating.
 76. The stentaccording to claim 72, further comprising at least one chemotherapeuticagent with the at least one coating.
 77. The stent according to claim73, further comprising at least one chemotherapeutic agent with the atleast one coating.
 78. The stent according to claim 70, furthercomprising at least one active ingredient with the at least one coating.79. The stent according to claim 71, further comprising at least oneactive ingredient with the at least one coating.
 80. The stent accordingto claim 72, further comprising at least one active ingredient with theat least one coating.
 81. The stent according to claim 73, furthercomprising at least one active ingredient with the at least one coating.82. The stent according to claim 70, wherein the at least one coatingcomprises a first coating and a second coating.
 83. The stent accordingto claim 82, wherein the first coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 84. The stentaccording to claim 83, wherein the second coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 85.The stent according to claim 82, further comprising at least onechemotherapeutic agent with the at least one coating.
 86. The stentaccording to claim 82, further comprising at least on active ingredientwith the at least one coating.
 87. A stent comprising: a substrate madefrom a ceramic material; at least one coating electrostatically coatedon the substrate; and at least one chemotherapeutic agent with the atleast one coating.
 88. The stent according to claim 87, wherein the atleast one coating comprises a first coating and a second coating. 89.The stent according to claim 88, wherein the first coating is from thegroup consisting of poly(ethylene oxide); poly(ethylene glycol);hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene; waxessuch as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 90. The stent according to claim 89, wherein thesecond coating is from the group consisting of poly(ethylene oxide);poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropyl cellulose;polyethylene; waxes such as microcrystalline wax; polyvinylidenefluoride and polycaprolactone.
 91. A stent comprising: a substrate madefrom a ceramic material; at least one coating electrostaticallyimpregnated with the substrate; and at least one chemotherapeutic agentwith the at least one coating.
 92. The stent according to claim 91,wherein the at least one coating comprises a first coating and a secondcoating.
 93. The stent according to claim 92, wherein the first coatingis from the group consisting of poly(ethylene oxide); poly(ethyleneglycol); hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene;waxes such as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 94. The stent according to claim 93, wherein thesecond coating is from the group consisting of poly(ethylene oxide);poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropyl cellulose;polyethylene; waxes such as microcrystalline wax; polyvinylidenefluoride and polycaprolactone.
 95. A stent comprising: a substrate madefrom a ceramic material; at least one coating electrostatically coatedon the substrate; and at least one active ingredient with the at leastone coating.
 96. The stent according to claim 95, wherein the at leastone coating comprises a first coating and a second coating.
 97. Thestent according to claim 96, wherein the first coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 98.The stent according to claim 97, wherein the second coating is from thegroup consisting of poly(ethylene oxide); poly(ethylene glycol);hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene; waxessuch as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 99. A stent compising: a substrate made from a ceramicmaterial; at least one coating electrostatically impregnated with thesubstrate; and at least one active ingredient with the at least onecoating.
 100. The stent according to claim 99, wherein the at least onecoating comprises a first coating and a second coating.
 101. The stentaccording to claim 100, wherein the first coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 102.The stent according to claim 101, wherein the second coating is from thegroup consisting of poly(ethylene oxide); poly(ethylene glycol);hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene; waxessuch as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 103. A stent comprising: a substrate made from a metalalloy; at least one coating electrostatically coated on the substrate;and at least one chemotherapeutic agent with the at least one coating.104. The stent according to claim 103, wherein the at least one coatingcomprises a first coating and a second coating.
 105. The stent accordingto claim 104, wherein the first coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 106. The stentaccording to claim 105, wherein the second coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 107.A stent comprising: a substrate made from a metal alloy; at least onecoating electrostatically impregnated with the substrate; and at leastone chemotherapeutic agent with the at least one coating.
 108. The stentaccording to claim 107, wherein the at least one coating comprises afirst coating and a second coating.
 109. The stent according to claim108, wherein the first coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 110. The stentaccording to claim 109, wherein the first coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 111.A stent comprising: a substrate made from a metal alloy; at least onecoating electrostatically coated on the substrate; and at least oneactive ingredient with the at least one coating.
 112. The stentaccording to claim 111, wherein the at least one coating comprises afirst coating and a second coating.
 113. The stent according to claim112, wherein the first coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 114. The stentaccording to claim 113, wherein the second coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 115.A stent comprising: a substrate made from a metal alloy at least onecoating electrostatically impregnated with the substrate; at least oneactive ingredient with the at least one coating.
 116. The stentaccording to claim 115, wherein the at least one coating comprises afirst coating and a second coating.
 117. The stent according to claim116, wherein the first coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 118. The stentaccording to claim 117, wherein the second coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 119.A stent comprising: a substrate made from a polymer; at least onecoating electrostatically coated on the substrate; and at least onechemotherapeutic agent with the at least one coating.
 120. The stentaccording to claim 119, wherein the at least one coating comprises afirst coating and a second coating.
 121. The stent according to claim120, wherein the first coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 122. The stentaccording to claim 121, wherein the second coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 123.A stent comprising: a substrate made from a polymer; at least onecoating electrostatically impregnated with the substrate; and at leastone chemotherapeutic agent with the at least one coating.
 124. The stentaccording to claim 123, wherein the at least one coating comprises afirst coating and a second coating.
 125. The stent according to claim124, wherein the first coating is from the group consisting ofpoly(ethylene oxide); poly(ethylene glycol); hydroxyethyl cellulose;hydroxypropyl cellulose; polyethylene; waxes such as microcrystallinewax; polyvinylidene fluoride and polycaprolactone.
 126. The stentaccording to claim 125, wherein the second coating is from the groupconsisting of poly(ethylene oxide); poly(ethylene glycol); hydroxyethylcellulose; hydroxypropyl cellulose; polyethylene; waxes such asmicrocrystalline wax; polyvinylidene fluoride and polycaprolactone. 127.A stent comprising: a substrate made from a polymer; at least onecoating electrostatically coated on the substrate; at least one activeingredient with the at least one coating.
 128. The stent according toclaim 127, wherein the at least one coating comprises a first coatingand a second coating.
 129. The stent according to claim 128, wherein thefirst coating is from the group consisting of poly(ethylene oxide);poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropyl cellulose;polyethylene; waxes such as microcrystalline wax; polyvinylidenefluoride and polycaprolactone.
 130. The stent according to claim 129,wherein the second coating is from the group consisting of poly(ethyleneoxide); poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropylcellulose; polyethylene; waxes such as microcrystalline wax;polyvinylidene fluoride and polycaprolactone.
 131. A stent comprising: asubstrate made from a polymer; at least one coating electrostaticallyimpregnated with the substrate; and at least one active ingredient withthe at least one coating.
 132. The stent according to claim 131, whereinthe at least one coating comprises a first coating and a second coating.133. The stent according to claim 132, wherein the first coating is fromthe group consisting of poly(ethylene oxide); poly(ethylene glycol);hydroxyethyl cellulose; hydroxypropyl cellulose; polyethylene; waxessuch as microcrystalline wax; polyvinylidene fluoride andpolycaprolactone.
 134. The stent according to claim 133, wherein thesecond coating is from the group consisting of poly(ethylene oxide);poly(ethylene glycol); hydroxyethyl cellulose; hydroxypropyl cellulose;polyethylene; waxes such as microcrystalline wax; polyvinylidenefluoride and polycaprolactone.